Aspen Global Change Institute (AGCI) Interdisciplinary Science Workshop: Decadal Climate Prediction; Aspen, CO; June 22-28, 2008

2007年政府间气候变化专门委员会(IPCC)评估报告AR4中出现的一个引人注目的问题是，人们对2030年左右的“短期”气候预测感兴趣。对于许多决策支持活动和影响来说，这是一个令人感兴趣的时间框架，但目前的模型和实验并未明确解决这一问题。目前提供的任何短期气候信息只是取自相对粗略的网格全球耦合气候模式，这些模式始于19世纪末，一直持续到2100年及以后的21世纪模拟的早期阶段。虽然这提供了关于气候系统在短期时间尺度上对外部强迫的反应的一些信息，但最近已经认识到，使用具有更高空间分辨率和可能观测到的初始状态的模型的不同类型的实验可以为未来几十年的决策支持和其他应用提供更好的区域气候变化信息。2006年夏天，阿斯彭全球变化研究所(AGCI)的一次会议首次提出了下一轮协调气候变化实验的实验设计，其中明确包括由国际气候模型界进行评估的短期气候预测。从那时起，世界气候研究计划(WCRP)、国际地圈/生物圈计划(IGBP)和政府间气候变化专门委员会(IPCC)开始着手这项工作，世界气候研究计划的气候可变性和可预测性计划(CLIVAR)以十年为目标进行预测，这是气候模型界面临的下一个重大研究挑战。2008年的AGCI会议延续了2006年会议的成果，不仅解决了与设计和运行短期气候预测(现在通常称为“十年预测”)有关的重大科学问题，还将这一概念推向了一个新的层次。会议还讨论了利用和应用这些信息进行决策支持和影响研究的重要问题。组织者邀请了从事十年预测研究的建模团体的美国和国际专家，以及将使用这些信息的决策支持和影响社区的代表。本届会议的成果将是一份白皮书，概述十年预测的知识现状、人们可以从这种实验中预期的成功程度、对这一问题所涉及的科学挑战的可能解决办法，以及对如何将这种类型的气候变化信息用于未来几十年的决策支持和影响分析的评估。更广泛的影响主要包括对近期(按代际时间尺度)气候变化的社会适应规划的十年预测的巨大价值。

A compelling issue that emerged from the Intergovernmental Panel for Climate Change (IPCC) Assessment Report, AR4, in 2007 was the interest in "short term" climate projections out to about 2030. This is a time frame of interest for many decision support activities and impacts, but is not explicitly addressed with current models and experiments. Any short-term climate information currently provided is simply taken from relatively coarse grid global coupled climate models in the early stages of 21st century simulations that began in the late 1800s and are run to 2100 and beyond. While this provides some information regarding the response of the climate system to external forcing on near-term time scales, it has recently been recognized that a different type of experiment using models with higher spatial resolution and possibly an observed initial state could provide better regional climate change information for decision support and other applications over the next few decades. An Aspen Global Change Institute (AGCI) session in the summer of 2006 first proposed an experimental design for the next round of coordinated climate change experiments that explicitly included short-term climate predictions to be performed for assessment by the international climate modeling community. Since then this has been taken up by World Climate Research program (WCRP), International Geosphere/Biosphere Program (IGBP) and the IPCC, with the WCRP's Climate Variability and Predictability Program (CLIVAR) targeting decadal prediction as the next big research challenge for the climate modeling community. The AGCI session in 2008 takes up where the 2006 session left off, and carries this concept to the next level by tackling not only the formidable science issues involved with designing and running short term climate projections (now more commonly referred to as "decadal prediction"). The session also addresses the important issues of the utility and application of this information for decision support and impacts research. The organizers invited U.S. and international experts from modeling groups doing research in decadal prediction, as well as representatives from the decision support and impacts communities who would use this information. Output from this session will be a white paper summarizing the current state of knowledge on decadal prediction, the degree of success one could expect from such experiments, possible solutions to the scientific challenges involved with this problem, and an assessment of how this type of climate change information could be used for decision support and impacts analyses the next few decades. Broader impacts include, primarily, the large value of decadal prediction for societal adaptation planning for near term (on generational time scales) climate change.